U.S. patent application number 12/083125 was filed with the patent office on 2009-09-17 for plasma display panel manufacturing system.
Invention is credited to Kinya Kisoda.
Application Number | 20090233515 12/083125 |
Document ID | / |
Family ID | 37942428 |
Filed Date | 2009-09-17 |
United States Patent
Application |
20090233515 |
Kind Code |
A1 |
Kisoda; Kinya |
September 17, 2009 |
Plasma Display Panel Manufacturing System
Abstract
The system includes a closed loop process line, multiple carts
which traverse the process line, a substrate magazine installed to
each cart, evacuation tube connectors (each holding an evacuation
tube) installed to each cart, an evacuation unit installed to each
cart to connect with the evacuation tube connector, a heat treating
oven in which a sealing and evacuation process is conducted, a
loading-unloading station provided at the process line, substrate
and evacuation tube delivery conveyors, control data driven robots
provided at the loading-unloading station, a panel discharge
conveyor which removes panels from the loading-unloading station,
and robot controllers which actuate the robots.
Inventors: |
Kisoda; Kinya; (Osaka-shi,
Osaka, JP) |
Correspondence
Address: |
IP GROUP OF DLA PIPER LLP (US)
ONE LIBERTY PLACE, 1650 MARKET ST, SUITE 4900
PHILADELPHIA
PA
19103
US
|
Family ID: |
37942428 |
Appl. No.: |
12/083125 |
Filed: |
October 7, 2005 |
PCT Filed: |
October 7, 2005 |
PCT NO: |
PCT/JP2005/018626 |
371 Date: |
April 4, 2008 |
Current U.S.
Class: |
445/73 ; 445/60;
700/254; 700/259; 901/47 |
Current CPC
Class: |
H01J 9/46 20130101; H01J
11/10 20130101 |
Class at
Publication: |
445/73 ; 445/60;
700/259; 700/254; 901/47 |
International
Class: |
H01J 9/38 20060101
H01J009/38; H01J 9/46 20060101 H01J009/46; B25J 19/02 20060101
B25J019/02; B25J 9/00 20060101 B25J009/00 |
Claims
1-20. (canceled)
21. A plasma display panel manufacturing system comprising: a
loop-shaped process line; multiple carts that traverse said process
line in a repeatedly starting and stopping sequence; a substrate
magazine associated with each cart, said substrate magazine sized
and shaped to accept at least a set of one pair of substrates; an
evacuation tube connector associated with each cart, said
evacuation tube connector accommodating a removable attachment of
an evacuation tube disposed in opposition to either one of said
pair of substrates; an evacuation unit associated with each cart
and connected with said evacuation tube connector, wherein
operation of said evacuation unit provides an evacuation process
through said evacuation tube; a heat treating oven installed in
said process line that applies a heat treating process to at least
a set of said one pair of substrates on said cart during traversal
therein to form connections between said pair of substrates and
between said evacuation tube and said substrates, and within which
an evacuation process is performed wherein gas residing between
said pair of substrates is evacuated by said evacuation unit on
said cart; a loading-unloading station adjacent said heat treating
oven along the traversing direction of said cart; a delivery system
at said loading-unloading station that delivers stacked pairs of
substrates and said evacuation tube; a robot at said
loading-unloading station and controlled by control data such that
said robot delivers said evacuation tube and said pair substrates
to said evacuation tube connector and substrate magazine on a cart
selected to enter said heat treating oven, seals/cuts off the
connection between said substrates and evacuation tube on said cart
which has exited said heat treating oven, disposes of the remaining
evacuation tube after cutting off from said substrates, and unloads
finished panels which have been separated from said evacuation
tube; a removal system which removes said finished panels from said
loading-unloading station; and a control system which controls
operation of said carts, evacuation unit, heat treating oven,
delivery system, robot, and removal system.
22. The plasma display panel manufacturing system according to
claim 21, wherein an electrical discharge gas supply unit supplies
an electrical discharge gas to the space between pairs of
substrates, through said evacuation tube in said evacuation tube
connector, during manufacture of the plasma display panel at a
point in time after the evacuation process has completed and before
the sealing and cutting off operation initiates.
23. The plasma display panel manufacturing system according to
claim 21, wherein said evacuation unit comprises an evacuation
pump, an open and closable evacuation valve, and an evacuation
valve controller, said evacuation valve controller operating to
close said evacuation valve when the pressure in the space between
said pair substrates has been monitored as having attained a
specified pressure.
24. The plasma display panel manufacturing system according to
claim 21, wherein said electrical discharge gas supply unit is
equipped with an electrical discharge gas supply source, an open
and closable supply valve through which an electrical discharge gas
from said electrical discharge gas supply source is fed to said
evacuation tube, and a gas supply valve controller which closes
said supply valve when the gas pressure in the space between said
pair substrates is monitored as having attained a specified
pressure.
25. The plasma display panel manufacturing system according to
claim 21, wherein a drive mechanism initiates, maintains, and
terminates traversal of said cart, and a locking device detachably
connects to the stopped cart to secure said cart to said process
line following termination of traversal.
26. The plasma display panel manufacturing system according to
claim 21, wherein said control system actuates operation of said
robot to attach said evacuation tube to said evacuation tube
connector and then place at least said one pair of substrates into
said substrate magazine to substantially simultaneously complete
placement of one substrate against said evacuation tube and the
loading operation of said pair substrates to said substrate
magazine.
27. The plasma display panel manufacturing system according to
claim 21, wherein said control system incorporates a supply action
setting function which, to provide automatic execution of an
operation in which said evacuation tube is taken from said delivery
system to said evacuation tube connector on said cart, obtains
positional image data indicating the cart's virtual stop position
and the evacuation tube's virtual attachment position, and outputs
control data, based on the positional image data, to actuate said
robot which executes the evacuation tube delivery operation.
28. The plasma display panel manufacturing system according to
claim 27, wherein said supply action setting function: obtains
image data of virtual stop position based on preset data indicating
a cart reference stop position, corrects a cart stop position from
a deviation between the virtual stop position and the reference
stop position, obtains image data of a virtual installation
position based on preset data indicating the reference installation
position for said evacuation tube connector from the cart stop
position, corrects the evacuation tube connector installation
position from a deviation between the virtual installation position
and the reference installation position, obtains virtual attachment
position image data for said evacuation tube, corrects the
evacuation tube attachment position from the deviation between the
virtual attachment position and the preset reference attachment
position for said evacuation tube, and outputs a corrected
evacuation tube supply action, in the form of control data, to said
robot which executes the supply action.
29. The plasma display panel manufacturing system according to
claim 21, wherein said control system incorporates an evacuation
tube removal correction function which obtains virtual standby
status image data for said evacuation tube at the removal standby
position, corrects the removal operation based on a variation of
virtual standby status data from preset standby status reference
data for said evacuation tube, and outputs the corrected removal
operation as control data.
30. The plasma display panel manufacturing system according to
claim 21, wherein said control system incorporates an evacuation
tube attachment correction function which obtains image data
relating to virtual status of a grip of said robot on said
evacuation tube, corrects the attachment operation based on a
deviation of virtual grip status data from preset grip status
reference data, and outputs a corrected attachment operation as
control data.
31. The plasma display panel manufacturing system according to
claim 21, wherein said evacuation tube connector is structured to
include an attachment orifice to which said evacuation unit is
connected and into which said evacuation tube is removably inserted
in a vertical orientation, and a ring seal installed within said
attachment orifice, said ring seal being structured to form the
air-tight sealing in the periphery of said evacuation tube by
applying pressure against or releasing pressure from around said
evacuation tube.
32. The plasma display panel manufacturing system according to
claim 31, wherein a vertically sliding structure facilitates
sliding movement of said evacuation tube connector in upward and
downward directions, regardless of any deformation of said ring
seal to place a top of said evacuation tube in pressurized contact
with one substrate of said pair of substrates, and a pressurizing
device is provided to apply pressure against said evacuation tube
connector, in an upward direction.
33. The plasma display panel manufacturing system according to
claim 21, wherein said substrate magazine has multiple segmenting
members defining substrate insertion spaces into which at least a
set of said one pair substrates is inserted, and said control
system incorporates a loading determination function which, to
provide automatic execution of operation through which said pair of
substrates is inserted into said substrate insertion space, obtains
dimensions of said substrate insertion space as image data, and
outputs control data, based on the image data, which indicates if
said pair of substrates can or cannot not be inserted into said
substrate insertion space.
34. The plasma display panel manufacturing system according to
claim 21, wherein said control system includes a loading correction
function which, to provide automatic execution of operation through
which said robot places said evacuation tube residing in said
evacuation tube connector in said cart against a ventilation port
of at least a set of one pair of substrates supplied from said
delivery system by said robot, obtains image data indicating the
center of said evacuation tube in an attached condition to said
evacuation tube connector and indicating the center of said
ventilation port at the loading standby position for said pair of
substrates, applies the center position image data to calculate the
variation to the center positions of said evacuation tube and said
ventilation port according to a reference loading operation
previously set to said robot for supplying said pair substrates to
said substrate magazine from the loading standby position, and
outputs the corrected loading operation as control data based on
the variation.
35. The plasma display panel manufacturing system according to
claim 21, wherein said substrate magazine includes multiple support
members at multiple locations, each support member being capable of
supporting said pair substrates through at least one inner support
piece proximal to said evacuation tube and through outer support
pieces further separated there from, said outer support pieces
supporting said pair substrates more slidable than said inner
support piece, thereby allowing less restricted movement of said
pair substrates placed thereon.
36. The plasma display panel manufacturing system according to
claim 35, wherein said outer support piece moves with a swinging
pendulum-like action.
37. The plasma display panel manufacturing system according to
claim 35, wherein said outer support piece is structured in the
form of a roller mechanism having a rotating axis passing through
an axial center of said evacuation tube.
38. The plasma display panel manufacturing system according to
claim 21, wherein said control system automatically controls
operation of an open and closable clamshell-type heater constructed
of two parts able to close around said evacuation tube to seal and
cut off said evacuation tube.
39. The plasma display panel manufacturing system according to
claim 21, wherein said control system automatically controls a
burner for melting said evacuation tube and an elevator device for
lowering said evacuation tube connector as means of stretching said
evacuation tube to perform a sealing and separating operation to
said evacuation tube.
40. The plasma display panel manufacturing system according to
claim 21, wherein said control system includes an unloading setting
function which, to provide automatic unloading of said finished
panels from said substrate magazine on said cart and their
placement in said removal system, obtains image data indicating a
virtual stop position of said cart and a virtual panel loading
position, and outputs control data, based on the image data, to
said robot to execute a panel unloading operation.
Description
RELATED APPLICATION
[0001] This is a .sctn.371 of International Application No.
PCT/JP2005/018626, with an international filing date of Oct. 7,
2005 (WO 2007/043159 A1, published Apr. 19, 2007).
TECHNICAL FIELD
[0002] This disclosure relates to a fully automatic system for the
manufacture of plasma display panels and the like.
BACKGROUND
[0003] Japanese Unexamined Patent Publication Nos. 2002-175758,
2002-324486, 2003-123648, 2003-141994 and 2003-146409 disclose
automation technology applied to components of a plasma display
panel manufacturing system.
[0004] While automation technology has been partially applied to
current plasma display panel manufacturing systems, there is a
growing need in the industry for manufacturing facilities which
integrate all manufacturing operations into a single continuous
automated system. Those operations, as noted here in sequence,
deliver assembly parts such as substrates and evacuation tubes,
load and arrange the substrates and evacuation tubes on a traverse
cart, seal and separate processes for the evacuation tubes after
applying a heat treatment and evacuation process in an oven, and
unload the finished panels.
[0005] In other words, a manufacturing system does not currently
exist wherein a continuous automated operation is conducted from
the time the substrates are first loaded onto the traversing cart
until they come out of the system as a finished display panel. What
is in common use today is a batch system in which the substrates
are manually loaded into the system. It is well-known that the
substrates shift their positions on the cart during the production
processes, which makes it difficult to maintain a uniform
positional relationship between the substrates and evacuation tubes
and to make up a completely automated system providing the
advantages of improved yield and reduced energy consumption while
removing the limitations to mass production which the current
system is faced with.
[0006] Thus, it could be advantageous to provide a plasma display
panel manufacturing system which provides for fully automated
installations of manufacturing plasma display panels and the
like.
SUMMARY
[0007] The plasma display panel manufacturing systems comprise:
[0008] a closed loop-shaped process line; [0009] multiple carts
which traverse the process line in a sequential repetitive
start-and-stop movement; [0010] a substrate magazine which is
installed to each cart and into which at least one pair of
substrates is loaded in a stacked configuration; [0011] an
evacuation tube connector which is installed to each cart and to
which is attached an evacuation tube facing the pair of substrates;
[0012] an evacuation unit which is installed to each cart and
connected with the evacuation tube connector wherein operation of
the evacuation unit provides an evacuation process through the
evacuation tube; [0013] a heat treating oven installed in the
process line and which forms connections between the pair
substrates and between the evacuation tube and pair of substrates
by applying a heat treatment to at least one pair of connected
substrates on the cart during traversal therein, and within which
an evacuation operation is performed wherein gas residing between
the two substrates is evacuated by operation of the evacuation unit
through the evacuation tube; [0014] a loading-unloading station set
up adjacent to the heat treating oven along the traversing
direction of the cart; [0015] a delivery system installed at the
loading-unloading station which delivers stacked pair substrates
and the evacuation tube; [0016] a robot installed at the
loading-unloading station and controlled by control data, the robot
delivering the evacuation tube and the pair of substrates to the
evacuation tube connector and substrate magazine on the cart which
is to enter the heat treating oven, sealing/cutting off the
connection between the substrates and evacuation tube on the cart
which has exited the heat treating oven, disposing of the remaining
evacuation tube after cutting off from the substrates, and
unloading finished panels which have been separated from evacuation
tube; [0017] a removal system which removes the finished panels
from the loading-unloading station; and [0018] a control system
which controls operation of the carts, evacuation unit, heat
treating oven, delivery system, robot, and removal system.
[0019] The systems may further include an electrical discharge gas
supply unit which, during manufacture of the plasma display panel
at a point in time after the evacuation process has completed and
before the sealing and separating process initiates, supplies an
electrical discharge gas to the space between the pair of
substrates through the evacuation tube in the evacuation tube
connector.
[0020] The systems may further be characterized by the evacuation
unit comprising an evacuation pump, a closable open evacuation
valve, and an evacuation valve controller which, when the pressure
in the space between the pair of substrates has been monitored as
having attained a specified level, closes the evacuation valve.
[0021] The systems may further be characterized by the aforesaid
electrical discharge gas supply unit being equipped with an
electrical discharge gas supply source, an open and closable supply
valve through which an electrical discharge gas from the supply
source may be fed to the evacuation tube, and a gas supply valve
controller which closes the supply valve when the gas pressure in
the region between the pair of substrates is monitored as having
attained a specified pressure.
[0022] The systems may further comprise a drive mechanism capable
of initiating, continuing, and terminating traversal of the carts,
and a locking device which connects to the carts to secure carts to
the process line following termination of their traverse.
[0023] The systems may further be characterized by the aforesaid
control system actuating the operation of the robot to attach the
evacuation tube to the evacuation tube connector and then to place
at least the pair of substrates into the substrate magazine to
simultaneously complete placement of one substrate against the
evacuation tube and the loading operation of the pair of substrates
to the substrate magazine.
[0024] The systems may further be characterized by the control
system incorporating a supply action setting function which, to
provide automatic execution of the operation through which the
evacuation tube is taken from the delivery system to the evacuation
tube connector on the cart, obtains positional image data
indicating the cart's virtual stop position and the evacuation
tube's virtual installation position, and outputs control data for
the evacuation tube delivery operation executed by the robot based
on the aforesaid positional image data.
[0025] The systems may further comprise a supply action setting
function: [0026] obtaining image data of virtual stop position
based on preset data indicating the cart reference stop position,
[0027] correcting the cart stop position from the deviation between
the virtual stop position and the reference stop position, [0028]
obtaining image data of virtual installation position based on
preset data indicating the reference installation position for the
evacuation tube connector from the cart stop position, [0029]
correcting the evacuation tube connector installation position from
the deviation between the virtual installation position and the
reference installation position, [0030] obtaining virtual
attachment position image data for the evacuation tube, [0031]
correcting the evacuation tube attachment position from the
deviation between the virtual attachment position and the preset
reference attachment position for the evacuation tube, and [0032]
outputting the corrected evacuation tube supply action, in the form
of control data, to the robot which executes the supply action.
[0033] The systems may further be characterized by the control
system incorporating an evacuation tube removal correction function
which, to provide an automated operation in which a robot removes
the evacuation tube from the delivery system, obtains image data
indicating the virtual standby status of the evacuation tube for
the removal standby position, corrects the removal operation based
on the variation of data indicating the evacuation tube's virtual
standby status from the preset standby status reference data, and
outputs the corrected removal operation as control data.
[0034] The systems may further be characterized by the control
system incorporating an evacuation tube attachment correction
function which, [0035] to provide automatic execution of an
operation in which the robot attaches the evacuation tube to the
evacuation tube connector, [0036] obtains evacuation tube virtual
grip status image data from the robot, [0037] corrects the
attachment operation based on the variation of preset evacuation
tube grip status reference data from virtual grip status data, and
[0038] outputs the corrected evacuation tube attachment operation
as control data.
[0039] The systems may further be characterized by the evacuation
tube connector being structured to include an attachment orifice to
which the evacuation unit is connected and into which the
evacuation tube is removably inserted in a vertical orientation,
and a ring seal which is installed within the attachment orifice,
the ring seal being structured to form the air-tight sealing in the
periphery of the evacuation tube by applying pressure against or
releasing pressure from around the evacuation tube.
[0040] The systems may further comprise a vertically sliding
structure which, to place the top of the evacuation tube in
pressurized contact with one substrate of the pair, moves the
evacuation tube connector along the vertical plane regardless of
any deformation of the ring seal, and by a pressurizing device
which applies pressure against the evacuation tube connector in an
upward direction.
[0041] The systems may further be characterized by the substrate
magazine having segmenting members defining substrate insertion
spaces into which at least one pair of substrates may be inserted,
and by the control system incorporating a loading determination
function which, to provide automatic execution of the operation
through which the pair of substrates is inserted into the substrate
insertion space, obtains the dimensions of the substrate insertion
space as image data, and outputs control data, based on that
dimensional image data, which indicates if the pair of substrates
can or cannot not be inserted into the substrate insertion
space.
[0042] The systems may further be characterized by the control
system incorporating a loading correction function which, [0043] to
provide automatic execution of an operation in which a robot places
the evacuation tube residing in the evacuation tube connector on
the cart against the ventilation port of at least one pair of
substrates which has been supplied from the delivery system by the
robot, [0044] obtains image data indicating the center of the
evacuation tube in the evacuation tube connector and the center of
the ventilation port at the substrate pair loading standby
position, [0045] applies the center position image data to
calculate the variation to the center positions of the evacuation
tube and the ventilation port according to a reference loading
operation previously set to the robot for supplying the pair of
substrates to the substrate magazine from the loading standby
position, and [0046] outputs a corrected loading correction
operation, as control data, based on the aforesaid variation.
[0047] The systems may further comprise the substrate magazine
having multiple support members at multiple locations, each support
member being capable of supporting at least one pair of substrates
through at least one inner support piece proximal to the evacuation
tube and at least one outer support piece further separated there
from, the outer support piece supporting the pair of substrates
with a lower frictional coefficient than the inner support piece,
thereby allowing less restricted movement of the substrates placed
thereon.
[0048] The systems may further be characterized by the aforesaid
outer support piece being able to move with a pendulum-like
action.
[0049] The systems may further be characterized by the aforesaid
outer support piece being structured as a roller mechanism with its
rotating axis passing through the axial center of the evacuation
tube.
[0050] The systems may further comprise the control system
automatically controlling the operation of an open and closable
clamshell-type heater constructed of two parts able to close around
the evacuation tube in order to seal off and separate the
evacuation tube.
[0051] The systems may further comprise the control system
automatically controlling a burner for melting the evacuation tube
and an elevator device for lowering the evacuation tube connector
as means of stretching the evacuation tube, in order to perform the
sealing and separating operation to the evacuation tube.
[0052] The systems may further be characterized by the control
system having an unloading setting function which, [0053] to
provide automatic execution of the unloading of the finished panels
from the substrate magazine on the cart and their placement in the
removal system, [0054] obtains image data indicating the cart's
virtual stop position and the virtual loading position of the
panels, and [0055] outputs control data, based on the aforesaid
image data, which actuates the robot to unload the panels.
[0056] The plasma display panel manufacturing systems may provide
installations of manufacturing plasma display panels and the like
through predominantly automatic controls.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] FIG. 1 is a schematic illustration of an example of an
entire plasma display panel manufacturing system.
[0058] FIG. 2 is an explanatory schematic of the cart used in the
system of FIG. 1.
[0059] FIG. 3 is a graph describing preferred temperatures in the
heat treating oven.
[0060] FIG. 4 is an explanatory schematic of the evacuation unit
installed to the cart shown in FIG. 2.
[0061] FIG. 5 is an abbreviated illustration of the cart traversing
mechanism applied to the car shown in FIG. 2.
[0062] FIG. 6 is a vertical cross section of an example of an
evacuation tube connector used in the system of FIG. 1.
[0063] FIG. 7 is an abbreviated cross section taken from plane D-D
of FIG. 6.
[0064] FIG. 8 is a vertical cross section illustrating the first
step of the process through which the evacuation tube is inserted
into the evacuation tube connector shown in FIG. 6.
[0065] FIG. 9 is a vertical cross section illustrating the second
step of the process through which the evacuation tube is inserted
into the evacuation tube connector shown in FIG. 6.
[0066] FIG. 10 is a vertical cross section illustrating the first
step of the process through which the substrates are placed over
the evacuation tube residing in the evacuation tube connector shown
in FIG. 6.
[0067] FIG. 11 is a vertical cross section illustrating the second
step of the process through which the substrates are placed over
the evacuation tube residing in the evacuation tube connector shown
in FIG. 6.
[0068] FIG. 12 is an abbreviated lateral view of an additional
preferred embodiment of the evacuation tube connector used in the
system of FIG. 1.
[0069] FIG. 13 is an abbreviated lateral view illustrating the
arrangement of the evacuation tubes in the tray.
[0070] FIG. 14 is an abbreviated lateral view illustrating an
additional arrangement of the evacuation tubes in the tray.
[0071] FIG. 15 is a lateral view of the FIG. 6 evacuation tube
connectors installed to the cart.
[0072] FIG. 16 is a plane view of the FIG. 15 evacuation tube
connectors installed to the cart.
[0073] FIG. 17 is a lateral view of the obtainment of image data
from the FIG. 6 evacuation tube connector.
[0074] FIG. 18 is a lateral view of a representative method of
obtaining image date of the evacuation tube applied in the system
of FIG. 1.
[0075] FIG. 19 is a lateral view of an additional method of
obtaining image date of the evacuation tube applied in the system
of FIG. 1.
[0076] FIG. 20 is an explanatory schematic illustrating the
relationship between the substrate and a dimensionally distorted
substrate magazine.
[0077] FIG. 21 is a flow chart illustrating the control process
through which the substrate is placed in the substrate
magazine.
[0078] FIG. 22 is a side view illustrating an example of a method
of obtaining image data relating to the ventilation port on the
substrate applied in the system of FIG. 1.
[0079] FIG. 23 is a plane view of the FIG. 22 method of obtaining
image data relating to the ventilation port on the substrate.
[0080] FIG. 24 is a lateral view of an example of the substrate
magazine used in the system of FIG. 1.
[0081] FIG. 25 is a plane view of the substrate magazine shown in
FIG. 24.
[0082] FIG. 26 is a detail lateral view of an example of the outer
support piece used by the FIG. 24 substrate magazine.
[0083] FIG. 27 is a lateral view of an additional example of the
substrate magazine used in the system of FIG. 1.
[0084] FIG. 28 is a plane view of the FIG. 27 substrate
magazine.
[0085] FIG. 29 is an enlarged plane view of an example of the outer
support piece applied to the FIG. 27 substrate magazine.
[0086] FIG. 30 is an enlarged plane view of the FIG. 29 outer
support piece.
[0087] FIG. 31 is a lateral view of the evacuation tube
sealing/separating unit used in the system of FIG. 1.
[0088] FIG. 32 is a plane view illustrating the operation of the
evacuation tube sealing/separating unit shown in FIG. 31.
EXPLANATION OF THE NUMERALS
[0089] 1 process line [0090] 2 cart [0091] 3 substrate [0092] 4
substrate magazine [0093] 5 evacuation tube [0094] 6 evacuation
tube connector [0095] 7 evacuation unit [0096] 8 heat treating oven
[0097] 9 loading-unloading station [0098] 10 substrate delivery
conveyor [0099] 11 evacuation tube delivery conveyor [0100] 12
evacuation tube handling robot [0101] 13 substrate loading robot
[0102] 14 evacuation tube sealing-cutting off robot [0103] 15 panel
unloading robot [0104] 16 panel discharge conveyor [0105] 17 cart
controller [0106] 18 oven controller [0107] 19 robot controller
[0108] 20 master controller [0109] 26 locking device [0110] 27
drive bar [0111] 28 connector block [0112] 29 drive dog [0113] 33
support beam [0114] 34 support fixture [0115] 34a inner support
piece [0116] 34b outer support piece [0117] 36 ventilation port
[0118] 39 evacuation pump. [0119] 40 evacuation valve [0120] 42
electrical discharge gas supply unit [0121] 43 gas supply source
[0122] 44 supply valve [0123] 50 pressure gauge [0124] 53
attachment orifice [0125] 54 ring-shaped seal [0126] 55 spring
[0127] 56 slide guide [0128] 65 lever [0129] 72 cylindrical roller
[0130] 73 support surface [0131] S substrate insertion space [0132]
T rotational center
DETAILED DESCRIPTION
[0133] The following provides a detailed description of a
representative example of a plasma display panel manufacturing
system with reference to the attached drawings. As illustrated in
FIGS. 1 through 4, the example of the system comprises: [0134] a
closed loop process line 1; [0135] multiple carts 2 traversing the
process line 1 in a repetitive sequential stop-and-start operation;
[0136] a substrate magazine 4 installed to each cart 2 and capable
of holding at least one pair of substrates 3; [0137] an evacuation
tube connector 6 installed to the cart 2 and removably holding an
evacuation tube 5 which faces the pair of substrates 3; [0138] an
evacuation unit 7 installed to the cart 2 and operating to evacuate
gas through the evacuation tube 5 in the evacuation tube connector
6; [0139] a heat treating oven 8 installed to the process line 1,
the oven 8 applying a heat treatment to at least one pair of the
substrates 3 on the cart 2 during traversal therein to form
connections between the pair of the substrates 3 and between the
substrates 3 and the evacuation tube 5, and within which gas in the
space between the pair of substrates 3 is removed by the evacuation
unit 7, which is installed to the cart 2, through the evacuation
tube 5; [0140] a loading-unloading station 9 provided adjacent to
the heat treating oven 8 of the process line 1 along the traversing
direction of the cart 2, [0141] a delivery system comprising a
substrate delivery conveyor 10 which delivers the pair of
substrates 3 to the process line 1, and an evacuation tube delivery
conveyor 11 which delivers the evacuation tube 5 to the process
line 1; [0142] robots 12 through 15 which are installed at the
loading-unloading station 9 and which operate according to control
data to deliver the evacuation tube 5 and the pair of substrates 3
to the evacuation tube connector 6 and the substrate magazine 4
respectively on the cart 2 prior to the cart 2 entering the heat
treating oven 8, to seal off and separate the evacuation tube 5
after the cart 2 exists the heat treating oven 8, to remove the
remaining evacuation tube 5 on the cart 2, and to unload the
finished panels from which the evacuation tube 5 has been
separated; [0143] a removal system comprising a panel discharge
conveyor 16 which removes the panels from the loading-unloading
station 9; and [0144] a control system comprising controllers 17-20
which control the operation of the carts 2, evacuation unit 7, heat
treating oven 8, the substrate delivery conveyor 10, evacuation
tube delivery conveyor 11, robots 12-15, and the panel discharge
conveyor 16.
[0145] The loading-unloading station 9, which is located adjacent
to the heat treating oven 8 along the cart 2 traverse path on the
process line 1, primarily has the function of supplying the
substrates 3 and evacuation tubes 5 to the cart 2, and of unloading
the processed panels from the cart 2. The loading-unloading station
9 includes the delivery system in the form of the substrate
delivery conveyor 10 which carries in a pair of frit sealed
substrates 3, the evacuation tube delivery conveyor 11 which
carries in the evacuation tube 5 having a frit seal 21 at its upper
edge, and the removal system in the form of the panel discharge
conveyor 16 which takes the processed panels out of the process
line. After the cart 2 exits the heat treating oven 8, the
processed panels on the cart 2 are removed, and then, new
substrates 3 and evacuation tubes 5 are loaded thereon after which
the cart 2 once again enters the heat treating oven 8.
[0146] The robots 12-15 which execute the previously described
operations are installed along the loading-unloading station 9.
More specifically, the evacuation tube handling robot 12 and
substrate loading robot 13 are positioned along the entering
traverse path of the cart 2 on the entrance 8a side of the heat
treating oven 8 according to the assembly sequence in which the
evacuation tubes 5 and substrates 3 are to be loaded on the cart 2.
The evacuation tube handling robot 12 carries the evacuation tube 5
from the evacuation tube delivery conveyor 11 to the evacuation
tube connector 6 on the cart 2, and the substrate loading robot 13
carries a pair of stacked substrates 3 from the substrate delivery
conveyor 10 to the substrate magazine 4 on the cart 2. The
evacuation tube sealing-cutting off robot 14 and panel unloading
robot 15 are positioned in sequence along the leaving traverse
direction of the cart 2 on the exit 8b side of the heat treating
oven 8.
[0147] The evacuation tube sealing-cutting off robot 14 seals and
separates the evacuation tube 5, which is connected with the
substrate 3 and is used in the evacuation process to remove gasses,
and then removes the separated evacuation tube 5 from the
evacuation tube connector 6. The panel unloading robot 15 unloads
the processed panels, which have been separated from the evacuation
tube 5, from the cart 2 and carries them to the panel discharge
conveyor 16. Other components also residing at appropriate
locations in the loading-unloading station 9 are cart controller 17
which controls traverse of the cart 2, the evacuation unit 7, and
other devices on the cart 2; oven controller 18 which controls the
operation of the heat treating oven 8; robot controller 19 which
controls operation of each robot; and master controller 20 which
controls the operation of a whole facilities including the delivery
conveyors 10 and 11 which carry in the substrates 3 and evacuation
tube 5 respectively, and the panel discharge conveyor 16.
[0148] The process line 1 is set up as production equipment within
a factory. The process line 1 includes parallel rails 23, upon
which ride each cart 2 through multiple wheels such as the eight
wheels 22, arranged in parallel pairs, and cart shuttles 24 and 25,
one of each being located at each end of the rails 23, connect and
transfer the cart 2 between the ends of two rail runs to form the
process line 1 as a closed loop in a rectangular configuration. The
heat treating oven 8 is installed over one run of the rails 23. The
loading-unloading station 9 is located along the other run of the
rails 23 parallel to the heat treating oven 8.
[0149] The manufacturing process operates by multiple carts 2
moving around the process line 1 in a sequential order. Each cart 2
rides on the rails 23 adjacent to the loading-unloading station 9,
and as shown in the drawings, after reaching the left terminal
point of the rails 23, is transferred to the rails 23 at the
entrance of the heat treating oven 8, by the cart shuttle 24, from
where the cart 2 moves into the heat treating oven 8. The cart 2
then moves through the heat treating oven 8, and as illustrated in
the drawings, once exiting the oven 8 and reaching the right side
termination of the rails 23, is transferred to the other run of the
rails 23 by the cart shuttle 25, thus completing one circuit of the
process line 1. In this manner, each cart 2 repeatedly starts and
stops traverse between the loading-unloading station 9 and the heat
treating oven 8 in a sequence coordinated with the time required
for the operations to be performed.
[0150] To automate the manufacturing process, this example of the
panel manufacturing system provides a motive mechanism for each
cart 2, the motive mechanism being capable of initiating,
continuing, and terminating the traversal of the cart 2, and
further provides a locking device 26 having the purpose of securing
the cart 2 to the process line 1 by detachable engagement when
traverse has terminated (see FIG. 5). The motive mechanism includes
a drive bar 27 movably installed along each of the rails 23 beneath
the cart 2, drive bar 27 moving with repetitive for and aft strokes
in the direction of the rails 23, and with repetitive opposing
axial rotations at specific rotational angles. A multiple drive
dogs 29 are attached to each drive bar 27, and each drive dog 29
controllably connects to or disconnects from connector block 28
installed to the bottom of each cart 2.
[0151] Drive bar 27 drives each cart 2 in the forward direction
through the engagement of the drive dog 29 to the connector block
28 on the cart 2, with the result that all of the carts 2 are
simultaneously driven forward for a specific stroke length. When
the traversal of the carts 2 is to be terminated, a forward axial
rotation of the drive bar 27 disconnects the drive dog 29 from the
connector block 28 on the cart 2. Next, with traversal of the carts
2 being stopped, the drive bar 27 drives axially rearward and
stops. The drive bar 27 then rotates in the opposite direction to
engage the drive dog 29 with the connector block 28 to allow the
cart 2 to be once again propelled in the forward direction.
Traversal of each of the carts 2 is started and stopped in this
repetitive manner, each traversal being equivalent to a specified
stroke length of the drive bar 27. As shown in FIG. 2, traversal of
the cart 2 is guided along the rails 23 by side guides 30 installed
to the left and right sides of the cart 2.
[0152] To secure the cart 2 at its stopped position, the locking
device 26, which is installed at the cart stop position, is able to
move into engagement with the connector block 28. While not shown
in the drawings, the locking device 26 may be structured in the
form of a cylinder mechanism installed next to the rails 23, and a
lock pawl 31 which is driven forward or rearward by the cylinder
mechanism to engage with or disengage from the connector block 28.
While the cart 2 is stationary, the cylinder mechanism drives and
engages the lock pawl 31 to the connector block 28 in response to
the disengagement of the drive dog 29 on the drive bar 27, and
drives and disengages the lock pawl 31 from the connector block 28
in response to the engagement of the drive dog 29. This mechanism
keeps the cart 2 stationary to be convenient to apply an automated
control. The drive mechanism of the cart 2 may also be structured
in a same manner by a self propelled mechanism through a rack and
pinion.
[0153] The substrate magazine 4 on the cart 2, which is shown in
FIG. 2, is structured to hold previously prepared pairs of the
substrate 3, each pair being arranged in a planar stack which may
be loaded onto the substrate magazine 4 in a vertical or horizontal
orientation. The substrate magazine 4 shown in FIG. 2 is designed
to support multiple substrates 3 in an overlapping horizontal
orientation, and is structured from four support posts 32 installed
to the cart 2, a plurality of support beams 33 supported by the
support posts 32, and multiple support fixtures 34 protruding from
the support beams 33 as means of supporting each pair of substrates
3 placed thereon.
[0154] The substrate 3 made be constructed of glass, synthetic
resin, metal, or other material appropriate to the task. A pair of
substrate 3 is constructed and handled integrally in a stacked
configuration with a frit seal applied around the external edge of
one of the pair and clips 35 securing the pair, as shown in FIG. 6.
The evacuation tube 5, which connects to a ventilation port 36
located in the corner of one of the substrates 3, has the purpose
of guiding the evacuation of gasses from between the substrates 3
within the heat treating oven 8, and also of guiding the
introduction of an electrical discharge gas to between the
substrates 3, after the aforesaid gasses have been evacuated,
during the plasma display panel manufacturing process.
[0155] A number of evacuation tube connectors 6 are installed to
each cart 2 equivalent to the number of pairs of substrates 3 to be
loaded thereon. As illustrated in FIG. 15, one connector pillar 37
is installed in the vicinity of ventilation port 36 formed in the
substrate 3 at a location external to the substrate magazine 4, and
projecting members 38, each to which an evacuation tube connector 6
is attached, are installed one above the other in the vertical
direction along the height of the connecting pillar 37. The
evacuation tube 5 is removably attached to the evacuation tube
connector 6. The upper portion of each evacuation tube 5 extends
upwardly toward each pair of substrates 3 supported on the support
fixtures 34 to face to the each lower side substrate 3 into which
the ventilation port 36 is formed, and the lower portion thereof
extends downward into the evacuation tube connector 6. A frit seal
21 is applied at the upper end of the evacuation tube 5 facing the
substrate 3.
[0156] The evacuation tube handling robot 12 and substrate loader
robot 13 place the evacuation tubes 5 and substrate pairs 3 onto
the cart 2 through an automatically controlled supply operation.
The robot controller 19 manages this supply operation so that the
robot 12 attaches one evacuation tube 5 to the evacuation tube
connector 6 after which the robot 13 places one pair of substrates
3 into the substrate magazine 4, for the purpose of completing an
assembly that evacuation tube 5 faces the substrate pair 3 along
with the loading operation of the substrate pair 3 to the substrate
magazine 4.
[0157] Each evacuation tube connector 6 is connected with the
evacuation unit 7, which is installed to the cart 2, for the
purpose of evacuating gasses, through the evacuation tube 5, from
the space between the two substrates 3 forming the pair. The gas
evacuation operation is executed while the cart 2 traverses through
the heat treating oven 8. As illustrated in FIG. 4, the evacuation
unit 7 comprises evacuation pump 39, open and closable evacuation
valve 40 which opens to allow gas evacuation, and controller 41
which closes the evacuation valve 40 when the pressure between the
two substrates 3 of the pair reaches a specific value. This
structure thus allows the evacuation process to be executed
automatically.
[0158] If necessary, an electrical discharge gas supply unit 42 may
be installed to the cart 2 in order to introduce an electrical
discharge gas into the space between the pair of substrates 3
during the plasma display panel manufacturing process. The
electrical discharge gas may be introduced, after the completion of
the evacuation process and before sealing and cutting off the
evacuation tube 5 through which the gas has been evacuated, while
the evacuation tube 5 is connected to the evacuation tube connector
6. The electrical discharge gas supply unit 42 comprises gas supply
source 43, supply valve 44 which opens or closes to allow or
prevent the flow of the electrical discharge gas from the gas
supply source 43 to the evacuation tube 5, and controller 41 which
closes the supply valve 44 when the pressure in the space between
the substrates 3 of the pair reaches a specific value. This
structure allows the electrical discharge gas delivery operation to
be controlled automatically. A hollow panel may be provided for a
process which does not require the introduction of an electrical
discharge gas.
[0159] A header 47 is connected to each evacuation tube connector 6
through an individual pipes 46 to which a solenoid valve 45 is
installed, the evacuation pump 39 is connected to the header 47
through an exhaust gas pipe 48 to which the evacuation valve 40 is
installed, and the gas supply source 43 is connected to the header
47 through a gas supply pipe 49 to which the supply valve 44 is
installed. The header 47 is provided for the purpose of proceeding
continuously the evacuation process and electrical discharge gas
introducing process to a multiplicity of substrate pairs 3
simultaneously by one evacuation pump 39 and one gas supply source
43. The controller 41 is structured from a pressure gauge 50 and a
control module 51. A pressure gauge 50 is installed to the header
47 to monitor the pressure between each pair substrates 3. A
monitoring signal from the pressure gauge 50 is output to the
control module 51 which controls the operation of each evacuation
valve 40, supply valve 44, and the evacuation pump 39.
[0160] When the evacuation valve 40 and solenoid valve 45 of the
individual pipes 46 open in evacuation process, the space between
the substrates 3 becomes continuous to the evacuation pump 39,
thereby resulting in the atmosphere of the space being evacuated at
a pressure of from 10.sup.-4.about.10.sup.-7 Torr. The electrical
discharge gas is introduced after the evacuation pump 39 operation
terminates and the evacuation valve 40 closes and further the
supply valve 44 opens, thereby resulting in the electrical
discharge gas, which may be Neon, Argon, Xenon or other appropriate
gas, flowing from the gas supply source 43 into the space between
the substrates 3 at a pressure of from 400.about.700 Torr.
[0161] A purging process may be applied in addition to the gas
evacuation wherein a purge gas supply pipe is connected to the
header 47 through a solenoid valve (not shown in the drawings), the
solenoid valve operating to connect the purge gas supply pipe to
either to the exhaust gas pipe 48 or gas supply pipe 49. When the
purging process is employed, the atmosphere between the substrates
3 is evacuated at the beginning of the gas evacuation process after
which the purge gas may be introduced, and then gas evacuation
process may be executed again.
[0162] As illustrated in FIG. 3, while moving from the entrance 8a
to the exit 8b in the heat treating oven 8, the cart 2 passes
through three different processing zones consisting of sealing
process block `A`, evacuation process block `B`, and cooling
process block `C`. The temperature within each processing block
A.about.C differs in order to conduct the desired heat treating
operation in which each traversing cart 2 passes through the
controlled temperature environment within each processing block
A.about.C. Because the cart 2 traverses the rails 23 placed
underneath the floor of the heat treating oven 8, an open space
exists along the entire length of the oven floor. An insulating
material member installed to each cart 2 seals the open space, and
the continual traverse of multiple adjacently aligned carts 2 along
the rails 23 forms a mechanism able to seal the open space in the
floor of the heat treating oven 8.
[0163] A radiant tube burner, electric heater, or other thermal
energy source is installed within a circulation passage defined by
a circulation flow generating baffle within the sealing process
block `A` in which the environment temperature gradually rises to
the sealing temperature along the length of block A, and within the
evacuation process block `B` in which the constant environment
temperature is slightly below the sealing temperature. The
environment within the heat treating oven 8 is heated by the
aforesaid thermal energy source and circulated by a fan as means of
applying thermal energy to the substrates 3 and so forth. The
external atmosphere introducing opening, cooling tube, or other
cooling source is installed, in addition to the same thermal energy
source installed in the block `A` or `B`, within the cooling
process block `C`. In the sealing process block `A`, the frit seal
melts to connect the pair of substrates 3 for sealing the space
thereof and to fix the evacuation tube 5 to either one of the
substrates 3. In the evacuation process block `B`, the evacuation
unit 7 operates to evacuate the atmosphere between the substrates 3
through the evacuation tube 5. An electrical discharge gas
insertion region 52 is provided between the exit 8b of the heat
treating oven 8 and the extraction cart shuttle 25 in order to
introduce the electrical discharge gas between the substrates
3.
[0164] The following will describe a preferred automated control
structure for the panel manufacturing process. A preferred
structure of the evacuation tube connector 6, to which the
evacuation tube 5 is attached under automatic control, will be
described as well as a preferred structure for the support of the
evacuation tube 5 held therein in light of the effects of the heat
treatment conducted in the heat treating oven 8.
[0165] As illustrated in FIGS. 6.about.11, the center section of
the evacuation tube connector 6 includes an attachment orifice 53
which connects to the evacuation unit 7 through the pipe 46, which
faces upward in order to allow for the connection of the evacuation
tube 5 thereto, and which accommodates the installation of an
elastic ring-shaped seal 54 therein which applies pressure against
and supports the evacuation tube 5 while sealing the periphery of
the tube 5 from the external environment. The evacuation tube
connector 6 further includes a vertically sliding structure, in the
form of a slide guide 56, which may form a pressurized connection,
regardless of any distortion of the seal 54, against the pair of
substrates 3 at the upper end of the evacuation tube 5 by slidably
supporting the connector 6 vertically, and a pressurizing device in
the form of spring 55 which applies upward pressure to the
evacuation tube connector 6.
[0166] With the lower portion of the evacuation tube 5 attached to
the evacuation tube connector 6 and the upper end thereof
pressurized against the substrate 3, the evacuation tube 5 bonds to
the ventilation port 36 as a result of the heated environment
within the heat treating oven 8. This is followed by initiation of
the evacuation process in which the atmosphere between the
substrates 3 is evacuated through the evacuation tube 5 fixed to
the evacuation tube connector 6. With the upper end of the
evacuation tube 5 in contact with the substrate 3, and with the
evacuation tube 5 maintained under pressure, the application of
heat to the connection forms a welded seal between the evacuation
tube 5 and substrate 3.
[0167] The evacuation tube connector 6 is additionally equipped
with a ring-shaped cooling jacket 57 installed around the
ring-shaped seal 54 with the purpose of cooling the seal 54 during
the heat treating process, an air supply/evacuation pipe 58
connected to the internal space of the seal 54, and upper and lower
plate members 59 and 60 between which the aforesaid components
reside within a sandwich-like structure. The entire evacuation tube
connector 6 is supported in a vertically movable condition by a
projecting member 38 through the spring 55 mounted beneath the
upper plate member 59, projecting member 38 being a cantilevered
member extending from the connector pillar 37. Element 61 is a
coolant supply pipe, and element 62 is a coolant discharge pipe.
The upper portion of the evacuation tube 5 is formed as a funnel
shape, and the lower portion, which is of uniform diameter, extends
to a specific position within the attachment orifice 53 through an
opening in the upper plate member 59 and through the ring-shaped
seal 54. With the evacuation tube 5 installed within the evacuation
tube connector 6, high pressure air supplied through the air
supply/evacuation pipe 58 to the internal space of the seal 54 has
the effect of expanding the seal 54 to form an air-tight seal
around the evacuation tube 5. Mechanical means may also be used to
expand and contract the seal 54.
[0168] A frit seal 21 is applied to the upper end of the evacuation
tube 5 before its lower portion is inserted into the attachment
orifice 53 in the evacuation tube connector 6. The upper end of the
evacuation tube 5 is positioned 1.about.2 mm above the lower
surface of the substrate 3 which may be loaded in a horizontal
orientation on the support fixture 34. High pressure air, which is
then supplied to the internal region of the ring-shaped seal 54
through the air supply/discharge pipe 58, swells the seal 54 which
grips the evacuation tube 5 and thus secures it in the evacuation
tube connector 6.
[0169] Following the mounting of the evacuation tube S in the
evacuation tube connector 6, the substrate 3 is loaded on the cart
2 while the ventilation port 36 simultaneously connects to the
evacuation tube 5. Because the evacuation tube S is secured in the
evacuation tube connector 6 with its upper end extending above the
lower surface of the substrate 3, the loading of the substrate 3
pushes the evacuation tube connector 6 downward against the tension
of the spring 55, thus forming a pressure-formed seal between the
upper end of the evacuation tube 5 and the lower surface of the
substrate 3. With the evacuation tube 5 mechanically pressurized
against and air-tightened to the evacuation tube connector 6, the
cart 2 enters the heat treating oven 8 where the sealing and
evacuation processes will be executed. Because the heated
environment forms a welded seal between the substrate 3 and
evacuation tube 5 with the two components in mutual pressurized
contact, a secure leak-proof bond is formed, a distortion of the
evacuation tube 5 does not arise during the sealing and evacuation
processes, and it allows the subsequent cutting-off process to be
executed more efficiently. For these reasons, this structure is
highly appropriate for an automatic sealing and separation
operation to the evacuation tube 5.
[0170] While it is preferable that the positional relationship
between the evacuation tube 5 and substrate 3 remain stable during
traversal of the cart 2 and also during the sealing and evacuation
operations, the forces of vibration, impact, and thermal expansion
and contraction may result in positional changes. For example,
excessive force being applied by the ring-shaped seal 54 against
the evacuation tube 5 may result in overcoming the strength of the
connection between the evacuation tube 5 and substrate 3. This may
lead to problems which could possibly interfere with the sealing
process, problems such as the evacuation tube 5 inclining or
breaking, or separation of the frit seal 21 from the lower surface
of the substrate 3. Moreover, if the relative horizontal positions
of the evacuation tube connector 6 and the substrate 3 were to be
disturbed, there is a possibility that the evacuation tube
connector 6 would not shift in parallel with the substrate 3, but
incline relative thereto. It must be taken into consideration that
an excessive unfavorable rotational or bending force applied to the
evacuation tube 5 could cause it to incline or break in a way which
would render the sealing process inoperable.
[0171] While the drawings describe the evacuation tube connector 6
as being supported by the projecting member 38 through the spring
55 installed beneath the upper plate member 59, this structure must
be carefully considered in terms of the previously noted problems
regarding the evacuation tube 5.
[0172] To solve the aforesaid problems, a slide guide 56 is
installed between the projecting member 38 and the lower plate
member 60. The slide guide 56 is constructed of a hollow cylinder
63 whose internal surface is made from carbon or other low friction
material, and a rod 64 which slides within the cylinder 63. The
cylinder 63 is secured to and supported by the underside of the
projecting member 38, and the rod 64 is installed to the lower
plate member 60. The slide guide 56 limits the movement of the
evacuation tube connector 6 to the vertical plane while restricting
it along the horizontal plane relative to the projecting member
38.
[0173] When the substrate 3 is put onto and the weight of the
substrate 3 presses the evacuation tube connector 6 downward a
small amount along a path guided by the slide guide 56, a mechanism
which allows the evacuation tube 5 to be displaced only along the
vertical axis while preventing movement along the horizontal plane.
The operation of the slide guide 56 and the mechanism by which the
evacuation tube connector 6 and evacuation tube 5 are pressed to
the substrate 3 by the spring 55 have the effect of maintaining a
high level of friction between the frit seal 21 and the substrate
3, which, in regard to the sealing process, prevents movement in
the joint formed between the ventilation port 36 and evacuation
tube 5 when the heated substrate 3 expands against the evacuation
tube 5 located at and pressed to the ventilation port 36. Moreover,
in regard to the sealing process, even though the substrate 3 may
be warped, the slide guide 56 has the effect of firmly pressurizing
the evacuation tube 5, by the spring 55, in an upward direction to
prevent the separation of the substrate 3 and frit seal 21.
[0174] Therefore, because this structure allows the sealing process
to be conducted without a clip 35 holding the substrates 3 and
evacuation tube 5 together, the effects of vibration and shock
which may be applied to the evacuation tube 5 and substrates 3 at
the timing of entering into the heat treating oven 8 are lessened,
dimensional distortion which can result from the thermal expansion
and contraction of components during the evacuation and evacuating
processes (especially side loads that would tend to rotate the
evacuation tube 5) is prevented, and the damage to the evacuation
tube 5 and the scarring which can be inflicted by the use of the
clip 35 is eliminated, thus simplifying preparatory work for the
sealing process and improving overall reliability. The pressurized
support of the evacuation tube 5 is easily maintained because the
evacuation tube connector 6 is supported by the spring 55 to be
movable only along the vertical plane, and because the evacuation
tube 5 is pressurized to the substrate 3 and supported in a
vertical orientation in a manner which prevents its reaction to
forces applied from directions other than the vertical.
[0175] As shown in FIG. 12, a pressurizing device other than the
spring 55 may be employed to apply pressure to the evacuation tube
connector 6. This device may be, for example, a weighted lever
mechanism in which a counterweight 66 is attached to one end of a
lever 65 with the other end connecting to and pressing upward
against the evacuation tube connector 6.
[0176] The following will describe the automated control operation
through which the evacuation tube 5 is connected to the evacuation
tube connector 6. In order to take the evacuation tube 5 from the
evacuation tube delivery conveyor 11 to the evacuation tube
connector 6 on the cart 2, the control system including the robot
controller 19 to control the evacuation tube handling robot 12 and
so on, has a supply action setting function obtaining virtual stop
position image data for the cart 2 and virtual attachment position
image data relating to the position of the evacuation tube 5 in the
evacuation tube connector 6 and outputting control data, based on
these image data, for the evacuation tube delivery operation
conducted by the evacuation tube handling robot 12.
[0177] The supply action setting function obtains image data of
virtual stop position based on preset data indicating the cart 2
reference stop position, [0178] corrects the cart 2 stop position
from the deviation between the virtual stop position and the
reference stop position, [0179] obtains image data of virtual
installation position based on preset data indicating the reference
installation position for the evacuation tube connector 6 from the
cart 2 stop position, [0180] corrects the evacuation tube connector
6 installation position from the deviation between the virtual
installation position and the reference installation position,
[0181] obtains virtual attachment position image data for the
evacuation tube 5, [0182] corrects the evacuation tube 5 attachment
position from the deviation between the virtual attachment position
and the preset reference attachment position for the evacuation
tube 5, and [0183] outputs the corrected evacuation tube supply
action, in the form of control data, to the evacuation tube
handling robot 12 which executes the supply action.
[0184] The control system, including the robot controller 19 to
control the evacuation tube handling robot 12, in order to provide
automatic execution of the operation through which the evacuation
tube handling robot 12 removes the evacuation tube 5 from
evacuation tube delivery conveyor 11 in the delivery system,
includes an evacuation tube removal correction function which
[0185] obtains virtual standby status image data for the evacuation
tube 5 at the removal standby position, [0186] corrects the removal
operation based on the variation of virtual standby status data
from preset standby status reference data for the evacuation tube
5, and [0187] outputs the corrected removal operation as control
data.
[0188] The control system, including the robot controller 19 to
control the evacuation tube handling robot 12, in order to provide
automated control of the operation in which the evacuation tube
handling robot 12 attaches the evacuation tube 5 to the evacuation
tube connector 6, includes an evacuation tube attachment correction
function which [0189] obtains image data relating to the virtual
status of the grip of the evacuation tube handling robot 12 on the
evacuation tube 5, [0190] corrects the attachment operation based
on the deviation of virtual grip status data from preset grip
status reference data, and [0191] outputs the corrected attachment
operation as control data.
[0192] Regarding the operation through which the evacuation tube 5
is carried into the loading-unloading station 9 by the evacuation
tube delivery conveyor 11 and delivered to the evacuation tube
connector 6, the evacuation tubes 5 are initially prepared for
delivery by their vertical placement in a tray 67 as illustrated in
FIG. 13, and, if necessary, by having a frit seal 21 applied on the
top end of each as illustrated in FIG. 14. An evacuation tube 5 is
then inserted into the attachment orifice 53 in the evacuation tube
connector 6. As the evacuation tubes 5 are of an easily breakable
glass material and may exhibit variations in their dimensions, the
length of each evacuation tube 5 is not uniform, and, as shown in
FIG. 13, may vary by .DELTA.L1 (standard length plus or minus 1
mm). With the frit seals 21 applied to the tops of the evacuation
tubes 5, as shown in FIG. 14, variation between the lengths of the
evacuation tubes 5 with applied frit seals 21 are shown as
.DELTA.L2. It is required, however, that the upper surface of the
evacuation tube connector 6 and that of the evacuation tube 5 are
at a uniform level.
[0193] For these reasons, the operation through which the
evacuation tube 5 is attached to the evacuation tube connector 6
has been done by hand as follows. First, one evacuation tube 5 is
manually removed from the tray 67 and placed in the attachment
orifice 53 in the evacuation tube connector 6 through visual
examination by a technician. The height of the evacuation tube is
then adjusted so that the distance between the upper surface of the
evacuation tube connector 6 and the upper edge of the evacuation
tube 5 remains uniform. Lastly, the evacuation tube 5, having its
installation height already adjusted, is sealed in the evacuation
tube connector 6 through the introduction of high pressure air into
the ring-shaped seal 54. This procedure, however, is not very
efficient nor is it productive as a result of the manual operation
through which the evacuation tube 5 is connected to the evacuation
tube connector 6. It is preferable to introduce an automatic
control completing a series of operation for assembling the
evacuation tube 5 to the evacuation tube connector 6 by means of
the automated evacuation tube handling robot 12.
[0194] In this case, after the cart 2 stops in front of the
evacuation tube handling robot 12, which is at a specific static
position, the installation operation is initiated. Even though a
reference stop position has been established, the cart 2 is not
always able to physically stop at that position. Moreover, the
position of the attachment orifice 53 in the evacuation tube
connector 6 will shift due to the tendency of the evacuation tube
connector 6 and substrate magazine 4 on the cart 2 to distort in
the heat treating oven 8 during the sealing and evacuation
processes. In addition, when the evacuation tube 5 is inserted into
the attachment orifice 53, due to the difference in the height of
the evacuation tube connector 6, it becomes difficult to maintain
the evacuation tube 5 in the correct condition in the evacuation
tube connector 6. Therefore, the following measures must be taken
to automate this process.
[0195] As illustrated in FIGS. 24 and 25, reference markers 1X, 1Y,
and 1Z are installed at the corner of the cart 2, marker 1X
indicating a reference point for the position of the cart 2 on the
horizontal X-axis parallel to the rails 23, marker 1Y indicating a
reference point for the position of the cart 2 on the horizontal
Y-axis perpendicular to the rails 23, and marker 1Z indicating a
reference point for the position of the cart 2 on the vertical
Z-axis perpendicular to both the X and Y-axes, in other words, the
position of the cart 2 along its height. Moreover, as illustrated
in FIGS. 15 and 16, a reference marker 1H is installed to each
projecting member 38 on the connecter pillar 37 of the cart 2 as
means of indicating reference positions for the projecting members
38. The reference markers 1X, 1Y, and 1Z may be formed as integral
parts of the cart 2, or may be separate components attached
thereto. In the same manner, the reference marker 1H may be
integrally formed to each projecting member 38, or may be attached
thereto as a separate component.
[0196] The evacuation tube handling robot 12, which is installed at
a static position at the loading-unloading station 9, has an arm
capable of three-dimensional positioning through linear and
rotational movements. A camera 68 is attached to the arm as means
of providing various types of control data, in the form of image
data, and as illustrated in FIG. 17, is capable of monitoring the
position of the attachment orifice 53 of the evacuation tube
connector 6. The robot arm executes a first operation through which
the coordinates for the center of the attachment orifice 53 are
established, and a second operation through which the evacuation
tube 5 in the tray 67 is gripped and inserted into the attachment
orifice 53. In the second operation, as illustrated in FIGS. 18 and
19, the top end of the evacuation tube 5, which is gripped in the
chuck 69 of the robot arm, is monitored by the camera 68 to measure
the distance from the chuck 69 to the top end of the evacuation
tube 5, or the distance from the chuck 69 to the top of the frit
seal 21 in case of being applied the frit seal 21 to the evacuation
tube 5.
[0197] The operation (step 1) through which the evacuation tube 5
is inserted into the evacuation tube connector 6 begins, when the
cart 2 moves to a position in front of the evacuation tube handling
robot 12 where the deviations (.DELTA.x1, .DELTA.y1, and .DELTA.z1)
between the cart 2 reference stop position and virtual stop
position are calculated based on the monitoring of the reference
markers 1X, 1Y and 1Z by the camera 68. Based on the calculated
deviations (.DELTA.x1, .DELTA.y1, and .DELTA.z1), the correction is
executed for the first measured position which is the robot arm's
first reference stop position. For example, if the X-axis deviation
component is +.DELTA.X, the robot arm stroke for the X-axis is
lengthened only by .DELTA.X. Conversely, if the X-axis deviation
component is -.DELTA.X, the robot arm stroke for the X-axis is
shortened only by .DELTA.X. The correction for the Y-axis and
Z-axis are conducted in the same manner. Therefore, even though
there may be an error in the cart 2 virtual stop position, the
first measured position of the robot arm is corrected to a position
where the camera 68 can monitor the reference marker 1H on the
projecting member 38.
[0198] The next operation (step 2) takes place with the robot arm
having stopped at the corrected first measured position. The
reference marker 1H on the projecting member 38 is monitored by the
camera 68, and the deviations (.DELTA.x2, .DELTA.y2, and .DELTA.z2)
are calculated between the reference installation position for the
evacuation tube connector 6 (the center of the attachment orifice
53) and the virtual installation position. In the same manner,
based on the calculated deviations (.DELTA.x2, .DELTA.y2, and
.DELTA.z2), the correction is executed for the second measured
position which is the robot arm's second reference stop position.
Therefore, even though there may be an error in the evacuation tube
connector 6 reference installation position, the second measured
position of the robot arm is corrected to a position where the
camera 68 can monitor the center of the attachment orifice 53.
[0199] The next operation (step 3) takes place with the robot arm
having stopped at the corrected second measured position. As
illustrated in FIG. 17, the camera 68 then moves to and monitors
the center of the attachment orifice 53, and the deviations
(.DELTA.x3, .DELTA.y3, and .DELTA.z3) are calculated between the
attachment orifice 53 reference center position and the virtual
center position. These three operations (steps 1 through 3)
determine the correct position (on the X, Y, and Z-axes) at which
the robot arm will stop over the evacuation tube connector 6 when
the evacuation tube 5 is to be attached.
[0200] Meanwhile, determination of the descending stop position (X,
Y, and Z1), that is, the setting of the position to which the robot
arm moves from the previous stop position (X, Y, and Z), is based
on data indicating the height of the evacuation tube connector 6 on
the Z-axis and data indicating the virtual length of the evacuation
tube 5 (the grip target) or the virtual length of the evacuation
tube 5 with the frit seal 21 attached. For example, if the position
at which the evacuation tube 5 is gripped by the robot arm's chuck
69, that is, the robot arm stop position, is determined as a
constant, the distance H1 from the chuck 69 to the top end of the
evacuation tube 5, or the distance H2 from the chuck 69 to the top
of the frit seal 21 is measured (see FIGS. 18 and 19), and a
calculation is executed to determine the deviation (.DELTA.L)
between the reference length and virtual length of the evacuation
tube 5. FIG. 18 illustrates the evacuation tube 5 in attachment
orifice 53 without a frit seal 21 applied, and FIG. 19 illustrates
the evacuation tube 5 in the attachment orifice 53 with the frit
seal 21 applied.
[0201] Therefore, the determination of the robot arm's descending
stop position (X, Y, and Z1) in relation to the virtual length of
the evacuation tube 5 is based on data indicating the deviation
(.DELTA.L) on the evacuation tube 5 and data indicating the height
of the evacuation tube connector 6 on the Z axis. For example, if
the deviation (virtual length minus reference length) between the
virtual length of the evacuation tube 5 and its reference length is
determined as +.DELTA.L, the descending stop position of the robot
arm will be a point only .DELTA.L lower from a position of zero (0)
deviation, and the upper end of the evacuation tube 5, or the frit
seal 21, will become an uniform relationship with the height of the
evacuation tube connector 6.
[0202] In the previously noted example, while the position of the
top of the evacuation tube 5, or the top of the frit seal 21, is
measured after the evacuation tube 5 is gripped by the chuck 69,
the position of the top of the evacuation tube 5 or frit seal 21
may also be obtained by a measurement performed before the
evacuation tube 5 is gripped by the chuck 69. In this case, the
position of the top of the evacuation tube 5, or frit seal 21, may
be previously measured by the camera 68 before the evacuation tube
5 is gripped by the chuck 69, the position at which the chuck 69
grips the evacuation tube 5 is corrected based on data indicating
that top position, and the descending stop position of the robot
arm is revised based on data indicating the height of the
evacuation tube connector 6.
[0203] This type of control of the evacuation tube handling robot
12 makes it possible to align the evacuation tube 5 with the
attachment orifice 53, adjust it in the correct position in regard
to its length, and accurately insert it into the attachment orifice
53. This can be done even with an error in the cart 2 virtual stop
position, the presence of manufacturing process deviations,
variations of the center position of the attachment orifice 53 in
the evacuation tube connector 6 resulting from thermal distortion
of the projecting member 38, and variations in the length of the
evacuation tubes 5 due to loose manufacturing tolerances. Moreover,
the camera 68 initially monitors the large variations in the cart 2
stop position, and then monitors the small variations in the center
position of the attachment orifice 53. Even if a field of vision on
the camera 68 may be narrow, the center of the attachment orifice
53 is accurately monitored by way of narrowing down a detection
area, thus aiding the operation through which the evacuation tube 5
is inserted into the attachment orifice 53.
[0204] The following will describe a preferred structure of the
automatic control mechanism through which the substrates 3 are
loaded onto the cart 2 on which the evacuation tube 5 has been
attached to the evacuation tube connector 6. The substrate magazine
4 incorporates multiple substrate insertion spaces `S`, which are
defined by multiple segmenting members in the form of support beams
33, each insertion space `S` capable of accommodating the insertion
of one pair of substrates 3. To automatically control the operation
of the substrate loading robot 13 in loading each pair of
substrates 3 into the substrate magazine 4, the control system,
which includes the robot controller 19 to control the substrate
loading robot 13 and so on, utilizes a loading determination
function which obtains image data indicating the dimensions of the
insertion space `S`, and which outputs a "go" or "no go" control
data, based on the data relating to the aforesaid dimensions, to
indicate if the pair of substrates 3 can or cannot be loaded into
the substrate insertion space `S`.
[0205] The control system, including the robot controller 19 for
controlling the substrate loading robot 13, incorporates a loading
correction function which, in order to have the ventilation port 36
of at least one pair of substrates 3 (which are supplied from the
substrate delivery conveyor 10 through the substrate loading robot
13) be brought into alignment with the evacuation tube 5 in the
evacuation tube connector 6 on the cart 2 by means of automatic
control, [0206] obtains image data indicating the center of the
evacuation tube 5 in an attached condition to the evacuation tube
connector 6 and indicating the center of the ventilation port 36 at
the loading standby position for the pair of substrates 3, [0207]
applies the aforesaid center position data to calculate the
variation to the center positions of the evacuation tube 5 and the
ventilation port 36 according to a reference loading operation
previously set to the substrate loading robot 13 for supplying a
pair of substrates 3 to the substrate magazine 4 from the loading
standby position, and [0208] outputs the corrected loading
operation as control data based on the aforesaid variation.
[0209] With the positioning space for the support beam 33 noted as
`D` and the height of the support fixture 34 noted as `h`, the
substrate insertion space `S` in which the pair of substrates 3 is
inserted between the upper surface of the support fixture 34 and
the lower surface of the support beam 33 has a vertical dimension
of `D` minus `h` (D-h). Moreover, in regard to the placement of the
substrate 3 on the support fixture 34, it is essential that the
centerline of the ventilation port 36 in the corner of the
substrate 3 is aligned with the centerline of the evacuation tube
5.
[0210] Because the support post 32 and support beam 33 are subject
to thermal distortion induced by the sealing and evacuation
processes taking place in the heat treating oven 8, the dimensions
of the space between the upper surface of the support fixture 34
and the lower surface of the support beam 33 may change from the
previously noted (D-h) dimension, thus resulting in
disproportionate values. Also, the position of the attachment
orifice 53 in the evacuation tube connector 6, that is, the
position of the centerline of the evacuation tube 5 mounted to the
evacuation tube connector 6, may also fall out of alignment due to
variations in the cart 2 stop position as well as the previously
noted thermal distortion. Furthermore, the position of the
ventilation port 36 in the substrate 3 may also be out of alignment
due to dimensional variations in the manufacturing process. As a
result of these factors, conventional processes load the substrate
3 onto the cart 2 manually, an operation which results in poor
process efficiency and reduced productivity. The system uses the
substrate loading robot 13 to automate this process by the robot
arm supporting the substrate 3, carrying it into the substrate
insertion space `S`, and placing it on the support fixture 34.
[0211] It must be considered, however, that damage could result
from a collision between the substrate 3 and support fixture 34, or
between the robot arm and support beam 33, if the size of the
substrate insertion space `S` (D-h) has been reduced to the point
where there is insufficient vertical space in which the substrate 3
insertion is induced. It must also be considered that, even though
the robot arm carries the substrate 3 to the same exact position, a
variation of the cart 2 stop position will result in misalignment
between the center of the ventilation port 36 on the substrate 3
and the center of the evacuation tube 5.
[0212] The substrate loading robot 13 is positioned at the
loading-unloading station 9 adjacent to the rails 23, and as
illustrated in FIG. 20, a reference marker 70 is installed at three
locations on the outer side of each of the support beams 33 which
are installed in a vertical step-like orientation on the cart 2.
The reference marker 70 may be formed as an integral part of the
support beam 33, or may be attached to the support beam 33 as a
separate component. The evacuation tube 5 is inserted into each
evacuation tube connector 6 on the cart 2 by the evacuation tube
handling robot 12. The reference markers 70 are monitored by the
camera (not shown in the drawings) mounted to the robot arm of the
substrate loading robot 13, the virtual height of each support beam
33 is measured, and the loading operation, through which the
substrate 3 is loaded onto the cart 2, is executed as explained
below.
[0213] As illustrated in the FIG. 21 flow chart, in `Step S1` of
the process, a calculation is conducted based on the height of the
reference markers 70, as monitored by the camera, in order to
determine the dimensions of the each space between the lower
surface of the support beam 33 and the support fixture 34 beneath
it. To be more specific, to determine the positions of the first
and second support members for example, as illustrated in FIG. 20,
height dimensions Z1a, Z1b, Z1c, and Z2a, Z2b, Z2c from a reference
level L0 corresponding to the upper surfaces of first and second
support fixtures 34 are calculated according to the height of each
monitored reference marker 70, after which the largest values from
among Z1a, Z1b and Z1c values (that is, the maximum Z1a, Z1b and
Z1c values) are taken, and the smallest values from among Z2a, Z2b,
and Z2c values (that is, the minimum Z2a, Z2b, and Z2c values) are
taken. The value indicating the size of the space is then
calculated as the minimum dimensions (Z2a, Z2b, Z2c) minus the
maximum dimensions (Z1a, Z1b, Z1c) minus D (Minimum (Z2a, Z2b,
Z2c)-Maximum (Z1a, Z1b, Z1c)-D). This value is applied as
representing the smallest space into which the substrate 3 may be
inserted.
[0214] In `Step S2`, when the size of the insertion space has been
calculated, a determination is made as to whether or not the robot
arm will be able to insert the substrate 3. A `YES` determination
results in the control sequence continuing to `Step S3`, while a
`NO` determination results in the control sequence jumping to `Step
S7`. In `Step S3`, as illustrated in FIGS. 22 and 23, the robot arm
moves the substrate 3 to a specific position above the fixed
position of the camera 71 which monitors the ventilation port 36
before insertion of the substrate 3, and the center of the
ventilation port 36 is measured at the stop position, in case of
bringing the substrate 3 over the support fixture 34 and
terminating by a predetermined robot arm operation.
[0215] In `Step S4`, with the camera on the robot arm continuing to
monitor the center of the evacuation tube 5, a determination is
made as to whether or not the center of the evacuation tube 5 is in
alignment with the center of the ventilation port 36 measured in
`Step S3`. A `YES` determination results in the control sequence
continuing to `Step S5`, while a `NO` determination results in the
control sequence jumping to `Step S9`. In `Step S5`, as it has been
determined that the center of the evacuation tube 5 and the
ventilation port 36 are in alignment, the robot arm carries the
substrate 3 between the support beams 33, and after aligning it
over the evacuation tube 5, places it on the support fixture 34 to
conclude the substrate loading operation.
[0216] After the substrates 3 have been loaded, a `Step S6` will be
executed, if necessary, in which the robot arm attaches a clip 35
to secure the substrates 3 to the evacuation tube 5. `Step S7`
indicates a condition in which the substrates 3 cannot be inserted
between the support beams 33; in other words, a condition in which
the support beams 33 have probably become distorted, resulting in
the activation of an alarm to alert the condition, and then the
control sequence proceeds to `Step S8` where the loading operation
of the substrates 3 onto the cart 2 is cancelled. In `Step S9`, as
the center of the ventilation port 36 has strayed from its
specified preset position, a deviation from the specified position
has occurred, so a deviation calculation is conducted.
[0217] The control sequence then proceeds to `Step S10` where the
robot arm stop position is corrected based on the calculation
conducted in `Step S9`. The control sequence then returns to `Step
S5` where the substrates 3 are loaded onto the support fixture 34.
This operation places the substrates 3 on the evacuation tube 5,
and then ends a loading of the substrates 3 onto the cart 2. This
operation is then repeated for each support beam 33.
[0218] In this operation in which the substrate loading robot 13
loads the substrates 3 onto the cart 2, the height of the substrate
insertion space `S` is measured, and a determination is made as to
whether or not the insertion space `S` is sufficient for the
insertion of the substrates 3. If the space is sufficient, in order
that the ventilation port 36 aligns with the evacuation tube 5, the
stop position of the robot arm may be corrected based on data
indicating the center of the ventilation port 36 in the substrate
3, and data indicating the center of the evacuation tube 5 in the
evacuation tube connector 6. Following this, in order that the
substrates 3 are carried over the support fixture 34, the substrate
loading robot 13 inserts the substrates 3 into the substrate
insertion space `S` through a path which avoids contact with the
peripheral components, thus making it possible to load the
substrates 3 in the correct position while increasing production
efficiency through automatic control of the operation.
[0219] The following will describe a mechanism which automates the
panel manufacturing operation by responding to thermally induced
misalignment, which results from the heat treating operation, of
the position of the substrates 3 in relation to the substrate
magazine 4. Multiple support fixtures 34 are installed to the
substrate magazine 4, each support fixture 34 being capable of
supporting at least one pair of substrates 3 loaded thereon. To
each support fixture 34 is installed at least one inner support
piece 34a adjacent to the evacuation tube 5, and an outer support
piece 34b installed at a further distance from the evacuation tube
5, the outer support piece 34b providing easier movement of the
pair of substrates 3 supported thereon compared to that of the
inner support piece 34a. The outer support piece 34b may be
structured as a rocking or swinging-type member. The outer support
piece 34b may also be structured as a roller mechanism having its
rotational center T passing through the center of the evacuation
tube 5 and supporting the pair substrates 3 thereon.
[0220] Each component of the cart 2 and the substrates 3 is subject
to thermal expansion and contraction as a result of the heat
treating process. It must be taken into consideration that the
expansion rates of the cart 2 components and substrates 3 are not
always uniform, and that the differences between their thermally
induced dimensional fluctuations may lead to external force being
applied to the joint between the evacuation tube 5 and substrate 3
as well as to the evacuation tube 5 itself. This will induce
misalignment between the evacuation tube 5 and the ventilation port
36 on the substrate 3 and breakage of the evacuation tube 5.
[0221] As a result of this potential problem, a separate flexible
tube is applied as the pipe 46 installed to the cart 2, through
which the evacuation tube connector 6 (in which the evacuation tube
5 is mounted) is supported by the projecting member 38, thus
forming a flexible mounting structure which does not restrict the
movement of the evacuation tube connector 6. While this structure
reduces, to a certain extent, the loads or external forces which
can be inadvertently applied to the evacuation tube 5 through the
evacuation tube connector 6, it should be kept in mind that it may
be an obstacle to the automatic control operations, cannot
completely eliminate problems caused by the aforesaid misalignment
and breakage and may significantly reduce the yield of an automated
plasma display panel manufacturing process.
[0222] It would be considered that it makes the thermal expansion
rate uniform between the substrates 3 and the support beam 33
having the support fixtures 34 or a base plate having the same
thermal expansion rate as the substrates 3 is mounted on the
support fixtures 34 arranged to the support beam 33. However, the
substrates 3 are made of glass, in case of constructing the support
beam 33 or base plate also out of glass, the other problems, such
as these components being prone to breakage, the increased overall
weight of the cart 2, and a reduction in thermal efficiency would
still have to be resolved.
[0223] As illustrated in FIGS. 24 and 25, on the cart 2, inner
support pieces 34a are attached to extending part 74 of the
projecting member 38 (which is supported by connecter pillar 37)
adjacent to the evacuation tube 5, and outer support pieces 34b are
attached to the support beam 33 (which is supported by the support
post 32) at locations further separated from the evacuation tube 5
than the inner support pieces 34a. The frictional coefficient
between the upper surfaces of the inner support pieces 34a and the
substrate 3 is greater than that between the upper surfaces of the
outer support pieces 34b and the substrate 3. For example, the
inner support pieces 34a may be made from a woven metal, a steel
net, or ceramic material to provide a roughly textured top surface,
and the outer support pieces 34b may be made from a metal or
ceramic with their top surfaces polished to a mirror-like finish.
The drawings show a structure in which two inner support pieces 34a
are attached to each projecting member 38 in nearly equivalent
proximity to the evacuation tube 5.
[0224] The substrate 3 rests on the top of the evacuation tube 5,
to which a frit seal 21 has been attached, and also on the upward
facing surfaces of the support pieces 34a and 34b in an orientation
in which the center of the evacuation tube 5 is in alignment with
the center of the ventilation port 36 of the substrate 3. As the
components constructing the cart 2 and the substrate 3 themselves
thermally expand and contract at different rates, a phenomenon
which induces variations in their dimensions, the substrate 3
resting on the upper surfaces of the inner support pieces 34a must
be supported in a way which isolates them from any movement which
could be induced by surrounding components. The outer support
pieces 34b support the substrate 3 at their upper surfaces through
a mechanism which allows the substrate 3 to slide along the
horizontal plane thereon in relation to the surrounding components
in order to prevent the connection part between the evacuation tube
5 and substrate 3, and the evacuation tube 5 itself, from being
affected by externally generated movements, thus preventing
misalignment between the evacuation tube 5 and the ventilation port
36 of the substrate 3 and damage to the evacuation tube 5. The
upper portion of each outer support piece 34b may be formed to a
partial spherical cross section or as a rotating roller which
allows the substrates 3 to slide while being supported thereon.
[0225] FIG. 26 describes an example of a differently structured
outer support piece 34b. In this structure, the outer support piece
34b incorporates a curved or partially spherical upper surface of a
head part 75 and a curved or partially spherical lower surface
formed of a pivot flange 77 pierced by a center shaft 76 which
extends from the head part 75 through a thru-hole 78 opened in the
support beam 33 so as to allow the pivot flange 77 to swing freely
against the perimeter of the upper portion of the thru-hole 78. The
center shaft 76 is able to swing around the intersecting point of
the pivot flange 77 at the center of the thru-hole 78. In other
words, the outer support piece 34b is designed to allow the
substrate 3 to move freely along the horizontal plane in response
to forces which induce a changing positional relationship between
the substrate 3 and the outer support piece 34b. Moreover, the
curved lower surface of the pivot flange 77 enables the top of the
head part 75 to remain at a uniform height regardless of the swing
angle of the center shaft 76.
[0226] FIGS. 27 through 30 describe another type of support
structure in the form of a roller mechanism. In this structure,
outer support piece 34b is formed as an open-top box 79 in which a
cylindrical roller 72 is placed in a freely rotatable condition.
The roller 72 in the box 79 rests on a support surface 73 formed of
two inclined planar surfaces extending from a center trough in
which the roller 72 resides when not affected by an external force.
As the sides of the box 79 extend upward from the two upwardly
inclined planar surfaces forming the support surface 73, a
structure is formed which prevents the escape of the roller 72 from
the box 79.
[0227] The outer support piece 34b is arranged that the rotational
center T (shown as a chain line in the drawing) of the roller 72
directs toward the evacuation tube 5. Concerning the aforesaid
thermal expansion and contraction, the outer support pieces 34b
allow the substrate 3 to more easily slide along the horizontal
plane than the inner support pieces 34a in relation to the
surrounding components in order to prevent the connection part
between the evacuation tube 5 and substrate 3, and the evacuation
tube 5 itself, from being affected by externally generated
movements, thus preventing misalignment between the evacuation tube
5 and the ventilation port 36 of the substrate 3 and damage to the
evacuation tube 5.
[0228] Although this structure describes two inner support pieces
34a, their number is not limited and may be specified as the
structure requires. Also, the evacuation tube 5 is not limited to
an upwardly facing orientation, but may also be disposed in a
downward facing orientation.
[0229] The following will describe the mechanism for easily
introducing the automated operation, by which the evacuation tube 5
is sealed and separated from substrate 3 after exiting the heat
treating oven 8. The control system, including the robot controller
19 for controlling the evacuation tube sealing-cutting off robot
14, automates the procedure with the aid of an open and closable
clamshell-type heater which closes around the evacuation tube 5 as
part of the sealing and separating operations.
[0230] The operation through which the evacuation tube 5 is sealed
and separated from its connection to the substrate 3 is executed
after the atmosphere between the two substrates 3 has been
evacuated. As the operation through which the evacuation tube 5 is
sealed and separated has been conventionally executed manually
using a gas burner to melt the appropriate point on the evacuation
tube 5, the need to automate this process is evident.
[0231] As illustrated in FIGS. 31 and 32, an evacuation tube
sealing/separating unit 80 is provided. The sealing/separating unit
80 comprises an insulated casing 82 formed from a pair of casing
parts 81, and a heating element (not shown in the drawings)
installed within each casing part 81, the heating element having
the purpose of applying heat to the external portions of the
evacuation tube. The casing 82 are arranged with one casing part 81
installed on a support seat 83, and the other installed on a
separate support seat 84. A power cylinder 85 is installed between
the support seats 83 and 84, and may be attached, for example, with
the cylinder body 86 connected to the support seat 84 and the
piston rod 87 connected to the support seat 83, thus forming a
structure through which the extension and retraction of the power
cylinder 85 is able to open and close the casing 82 in the form of
moving one casing part 81 relative to other casing part 81.
[0232] Each of the two casing parts 81 is structured as a hollow
half cylinder filled with an insulating material, having a
semicircular channel 88 formed at the center. When the two casing
parts 81 are brought together, that is, closed against each other,
the semicircular channels 88 form an enclosed cylindrical space. A
heating element is installed along the channels 88. With the casing
82 in a closed condition and the two casing parts 81 in mutual
contact, the semicircular channels 88 form a thru-hole 89 which
functions as an evacuation tube chamber. A shaft 90 is attached to
the support seat 84, and the clip 35 is attached to the top of the
shaft 90 to secure the substrates 3.
[0233] The electrical discharge gas sealing process is complete
after the atmosphere between the substrates 3 has been evacuated.
As illustrated in the drawings, the evacuation tube sealing-cutting
off robot 14 positions the casing parts 81 on opposite sides of the
evacuation tube 5, and then attaches the evacuation tube
sealing/separating unit 80 to the substrates 3 by the grip of the
clip 35. The attachment of the clip 35 is executed by movement of
the robot arm through the use of image data relating to the
position of the substrates 3 as monitored by the camera on the
robot arm. The retracting movement of the power cylinder 85 brings
the casing parts 81 into mutual contact to form a single structure.
To be more specific, the evacuation tube 5 resides in the thru-hole
89 and is surrounded by the heater, when the casing 82 is in this
closed condition. The heater is then actuated to heat the space
around the evacuation tube 5 for a specific period of time. The
sealing operation is executed when the region around the evacuation
tube 5 comes to a uniform melting temperature. The continued
application of electrical power to the heater will result in the
subsequent separation of the sealed part.
[0234] This structure makes it possible to automate the sealing and
separating operations applied to the evacuation tube 5, increases
the efficiency of the operation, and by using the evacuation tube
sealing-cutting off robot 14 for detachably attaching and removing
the evacuation tube sealing/separating unit 80 to and from the
substrate 3 with the clip 35, eliminates the preparation of the
units 80 for every substrates 3, thus reducing the number of
components required.
[0235] The automated operation through which the evacuation tube 5
is sealed and separated may also be conducted using a burner
instead of a heater. The control system, including the robot
controller 19 for controlling the evacuation tube sealing-cutting
off robot 14, incorporates a sealing and cutting-off function which
is proceeded by using a burner for melting the evacuation tube 5
and an elevator device for lowering the evacuation tube connector 6
as means of stretching the evacuation tube 5, in order to perform
the sealing and separating operation to the evacuation tube 5. In
other words, the burner may be attached to the robot arm of the
evacuation tube sealing-cutting off robot 14 which operates to
attach the aforesaid clip 35 to the substrates 3. For example, the
elevator device may be installed to lower the evacuation tube
connector 6 and thus change its position in relation to the
projecting member 38 along the vertical plane. Automated burner
position control may be conducted using a method similar to the
previously described automated operation in which image data is
used to control the insertion of the substrates 3 into the
insertion space `S`, or the insertion of the evacuation tube 5 into
the attachment orifice 53.
[0236] In the same manner, image data obtained from a camera is
used to control the operation through which the evacuation tube
sealing-cutting off robot 14 grips the part of the evacuation tube
5 remaining in the evacuation tube connector 6 after the sealing
and separating operation. The high pressure air is removed from the
ring-shaped seal 54 in the evacuation tube connector 6 through the
air supply/evacuation pipe 58 in order to release the grip of the
seal 54 on the remaining part of the evacuation tube 5, and then
the remaining part of the evacuation tube 5 may be removed and
discarded. The remaining part of the evacuation tube 5 may be
removed by the same evacuation tube handling robot 12 which
delivered the evacuation tube 5 to the cart 2. If this is done, the
air line leading from the evacuation tube connector 6 to the
evacuation pump 39 should, as much as possible, be prevented from
opening to the atmosphere.
[0237] Automatic control is then applied to the operation through
which the finished panel is removed from the cart 2, the panel
having been previously sealed and separated from the evacuation
tube 5. In order to automatically remove the panel from the
substrate magazine 4 on the cart 2 and place it on the panel
discharge conveyor 16, the control system, which controls operation
of the panel unloading robot 15 through the robot controller 19,
applies an unloading setting function through which the cart 2
virtual stop position image data and virtual panel loading position
image data are obtained and used in the output of control data
which controls the operation through which the panel unloading
robot 15 unloads the panels. This automatic control function
operates in the same manner as that applied to the loading of the
substrates 3.
[0238] In the operation through which the panels are removed from
the cart 2, traversal of the cart 2 stops at a point in front of
the panel unloading robot 15 after which the variation between the
cart 2 reference stop position and virtual stop position is
calculated based on the reference markers 1X, 1Y, and 1Z monitored
by the camera. The calculated variation is used for modifying the
first measured point which becomes the first reference stop point
for the robot arm. Therefore, even though the cart 2 may have
stopped at the virtual stop position different from the reference
stop position, the robot arm's first measured point can be
corrected to the position where the camera can monitor the
reference marker 1H on the projecting member 38.
[0239] In Step 2, the robot arm stops at the corrected first
measurement point, the camera monitors the reference marker 1H on
the projecting member 38, and the extent of variation between the
panel's reference loading position and virtual loading position is
calculated. The second measured point, which is the second
reference stop point for the robot arm, is then corrected based on
the aforesaid calculated variation. The correct stop point for the
robot arm in relation to the panel's virtual loading position is
thus determined in Steps 1 and 2.
[0240] Applying this type of automatic control mechanism to the
operation of the panel unloading robot 15 makes it possible to
bring the robot arm to the correct panel unloading position and to
appropriately unload the panels from the cart 2 even in cases where
the cart 2 has not stopped at its proper stop position, falloffs in
manufacturing tolerances have altered dimensions, or components
have been subjected to thermal distortion.
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